RESULTS: Mean serum sFlt1 and the sFlt1/PlGF ratio were higher in subjects who developed early-onset (less than 34 weeks) preeclampsia, as compared with subjects without preeclampsia, from 22 weeks gestation onward. In subjects who developed late-onset (34 weeks or later) preeclampsia, sFlt1 was significantly increased after 31 weeks' gestation. The sFlt1/PlGF ratio at 22-26 weeks was highly predictive of early-onset preeclampsia. The within-woman rate of change of the sFlt1/PlGF ratio was predictive of overall preeclampsia risk.

CONCLUSIONS: In high-risk women, serum sFlt1 and the sFlt1:PlGF ratio are altered prior to preeclampsia onset and may be predictive of preeclampsia. Larger studies are needed to confirm these findings.